Listen to Robert Emmerich introduce The Big Apple, a hit song from 1937. Music written by Bob and performed by Tommy Dorsey's Clambake Seven with Bob on piano. Lyrics written by Buddy Bernier and sung by Edythe Wright. Audio provided by Dorothy Emmerich.

"Horse sense is something a horse has that keeps him from betting on people. (MBS broadcast)” was cited in Reader’s Digest in 1942. “Horse sense is something a horse has that keeps him from betting on a human being” was cited in print in February 1943, but no author’s name was given. “Horse-sense is something a horse has to keep him from betting on people” was cited in a March 1943 newspaper comic “daffynition” (daffy definition), but, again, no author’s name was given. “Credit Phil Baker for today’s philosophy: ‘Horse sense is what keeps horses from betting on people’” was cited in May 1943; Phil Baker (1896-1963) was a popular radio personality.

Comic actor W. C. Fields (1880-1946) is often credited with the line, but it’s uncertain if he ever said it.

18 February 1943, The Belton Journal and Bell County Democrat (Belton, TX), “A Little Fun: Jokes to Make You Laugh,” pg. 9, col. 1:
“Horse sense is something a horse has that keeps him from betting on a human being.”

14 March 1943, Port Arthur (TX) News, “Daffynition,” pg. 5, col. 5:
HORSE-SENSE IS SOMETHING A HORSE HAS TO KEEP HIM FROM BETTING ON PEOPLE.

Google News Archive
16 June 1943, Edmonton (Alberta) Journal, pg. 15, col. 6 classified ad:
HORSE SENSE
is something a horse has that keeps him from betting on people but common sense tells you if you need a home and acreage you can bet the FARRELL AGENCIES will pick a winner every time.

Google BooksHow to Be Human on the Job
By Wallace Strathern
New London, CT: National Foremen’s Institute
1950
Pg. 9:
AN associate of mine defines “horse sense” as, “That which keeps horses from betting on people.”

Google BooksThe Little Red Book of Horse Wisdom
Edited by Yvette Grant
New York, NY: Skyhorse Pub.
2012
Pg. ?:
Horse sense is the thing a horse has which keeps it from betting on people.
—W. C. FIELDS (1880–1946)